Hitherto, a light emission device for use in an illuminator and the like has been developed which emits a white light by emitting light from a phosphor employing, as an excitation light, light emitted from an LED element.
As such a light emission device, there is known, for example, a light emission device which obtains a white light by employing a phosphor converting a blue light emitted from an LED element to a yellow light to emit the yellow light and mixing the blue light and the yellow light; or a light emission device which obtains a white light by employing a phosphor converting an ultraviolet light emitted from an LED element to a blue light, a green light and a red light to emit the blue, green and red lights and mixing the three color lights emitted from the phosphor.
As a light emission device, a light emission device has been developed which has a structure that an LED chip is directly sealed by a curable resin with a phosphor dispersed therein. Application of this light emission device expands in a field such as a headlight for cars and the like in which high luminance is required, and at the present, improvement of the output power of a white light emitting LED is carried out, which is accompanied by heat generation of the LED chip. Therefore, when a phosphor dispersed in a sealing agent is provided directly on an LED element as described above, the phosphor may deteriorate on account of heat generation of the LED element.
In order to solve the problem as described above, there has been proposed a technique in which an LED is sealed by a phosphor-dispersing ceramic but not by a phosphor-dispersing resin, whereby deterioration of a sealing agent used is prevented (see, for example, Patent Document 1.).